Photoelectric cell



July 9,1946. I A-. H; LAMB v I 2,403,863

PHOTOELECTRIC CELL Filed Aug. 26 1944 This invention relates to photoelectric cells of providea photocell having a current collector of the; barrier layer type and particularly to the consmall area located substantially centrally of the struction or arrangement of the current collector translucent electrode layer. More specifically, an system associated with the translucent upper object is to provide a photocell having a central electrode of the cells. r or approximately central aperture surrounded by Photocells as 'manufactured commercially in a current-collector" ring of smallsize, and a tervarious shapes have usually comprised a back minal connection welded or soldered to the curelectrode of desired shape carrying a layer of rent collector ring.

light-sensitive material such as copper oxide or These and other objects and advantages of the crystalline selenium, atranslucent electrode layer invention will be apparent from the following upon the light-sensitive material, and a current specification when taken with the accompanycollector rib of cadmium or other soft metal ing drawinginwhich:

, upon and extending around the periphery of the Fig. 1 is a central section through a photoelectranslucent electrode. The terminal connections trio cell embodying the invention; and to the photocells have usually taken the form of 5 Fig.2 is an elevation of the same. spring fingers bearing upon the back electrode In the drawing, the reference numeral l idenand the current collector rib with substantial tifies a circular disk electrode of iron or a ferpressure. 7 rous alloy that has a small central aperture. A

The current collector or pick-up rib prevents layer 2 of material, for example selenium, is de- Patented July 9, 1946 PHOTOELECTBIG CELL -Anthony H; Lamb, Hillside, N. I, assignor to {Weston Electrical Instrument Corporation, Newark, N. J a corporation of New ersey Application August 26, 1944, serial No. 551,416

' sjciai'rils; (01.; iae' gsci) UNITED srrss PAT T OFFICE a short-circuiting of th cell through a crushing 0 posited upon and converted in known manner of the translucent electrode layer by the spring into the crystalline light-sensitive state, and a terminal fingers, but the relatively thick and translucent outer electrode layer 3 is deposited opaque pick-up rib decreases the current output or formed upon the layer 2. The particular procby blocking light from a substantial portion of ess steps for forming the multiple layer photothe light-sensitive layer and increases the dark electric cell as so far described are not essential leakage of thephotocell. The term dark leakfeatures of the invention and any known or deagc is applied to the effect of the portion of sired'processes may be employed.

the light-sensitive layer that is not exposed to In accordance with this invention, a small dilight and which forms a current-conducting path ameter and small area ring 4 of cadmium or a in parallel with the external photocell circuit. soft metal is deposited around the central aper- The light-sensitive layer is of high resistance but ture of the cell assembly by a metal spraying that portion which is not exposed to light forms process, A spring terminal connection may be an internal path through which a part of the genmade to the collector ring but it is convenient, and erated current circulates, thereby diminishing usually preferable, to form a permanent metallic the current in the external or useful circuit. Furconnection. As illustrated, the strands 5 of a flexthermore, the formation of the current pick-up ible insulated terminal conductor 6 that extends rib by a metal-spraying process results in root through the central aperture are separated and leakage that may be substantial or, in some inbent outwardly to overlie the ring 4 to which stances, may short-circuit the cell. The sprayed they are mechanically and electrically connected metal of the rib penetrates to some extent into by weld metal or solder 1. The other'end of the the crystalline lightsen'sitive layer to form terminal conductor 6 may be provided with a lug roots that approach the back electrode to a or contact 8 for connecting the cell into an exgreater or less extent, thereby reducing the reternal circuit. One end of an insulated wire 9 sistance of the dark area of the light-sensitive is secured. to the back electrode I by solder or layer to a value substantially less than that which weld metal I0, and a lug or contact H is soldered would obtain if the current collector rib could i r or clamped upon the other end of the insulated be separately formed and pressed upon the transwire 9.

lucent electrode layer. 7 The small area of the collector ring 4, as com- Objects of the present invention are to provide pared with the conventional collector ring .ele-

photocells that have a substantially increased ments at the periphery of the outer electrode current output for a photocell of any given size. layer, results in an increased current output due An object is to provide photocells with current to the increased active area of the translucent collector systems that increase the useful lightelectrode layer 3 and to the reductions in dark sensitive areas of the photocells and that reduce leakage and root leakage currents. It is to be dark leakage and root leakage. An object is to noted that the length of the path of current flow from any remote part of the electrode layer to the central collector ring 4 is substantially the same as in the prior construction that included a peripherally arranged collector ring. The advantages of a small current collector area are thus obtained without introducing any conditions that ofiset the advantages.

It is to be understood that the invention is not limited to the construction herein'illustrated and described as various changes may be made in the size, shape and arrangement of the cell components and terminal connections without departing from the spirit of my invention as set forth in the following claims.

I claim:

1. A photoelectric cell of the current-generating type including a back electrode, a layer of light-sensitive material on the back electrode, a translucent electrode on the light-sensitive layer, and a current collector rib of soft metal deposited upon a part of the translucent electrode; characterized by the fact that said current collector rib is limited to a small area located substantially centrally of the translucent electrode.

2. A photoelectric cell of the current generating type comprising a back electrode having an electrode, said back electrode being a circular disk with a central aperture, a current-collecting ring deposited upon said outer electrode at the periphery of said central aperture, and a terminal connection extending through said aperture and soldered to said collecting ring.

5. A photoelectric cell as recited in claim 4, wherein said connection comprises a multistrand insulated, conductor, the ends of the several strands being separated from each other and soldered to said current collector ring.

ANTHONY H. LAMB. 

